| 摘要 |
PROBLEM TO BE SOLVED: To prevent lost contrast at a high luminance part and missed information in the direction of a scan line while restricting the hallation of the high luminance part by performing an edge intensifying processing and then, a compression of gradation for image data with pixel values larger than a threshold. SOLUTION: An analog X-ray image signal outputted from a TV camera 14 is converted to a digital data by an A/D converter 21 to be sent to a nonlinear conversion circuit 22 and an output image data (b) of the nonlinear conversion circuit 22 is separated by a threshold processing circuit 23 into image data (c) with the pixel values smaller than a specified threshold and those (d) with the pixel values larger than it. The image data (d) with the pixel values larger than the threshold undergo an edge intensifying processing with a two-dimensional space frequency processing circuit 24 to be compressed in the direction of gradation by a gradation conversion circuit 25. Then, the results are added to the image data (c) with the pixel values smaller as separated by the threshold processing circuit 23 and after another processing with a processing circuit 27, the processed data is returned to an analog image signal by a D/A converter 28. |
